大尺寸脉冲涡流检测热力管道腐蚀缺陷

Large-scale Pulsed Eddy Current Testing of Corrosion Defects in Heating Pipeline

基于时域有限差分算法,对大尺寸脉冲涡流检测热力管道腐蚀缺陷进行仿真模拟,并进行试验验证。利用非均匀网格的时域有限差分算法仿真模拟了不同长度、不同深度的环状凹槽,以及不同管径和不同埋深的情况,对于大多数情况,中期感应电压差异大于晚期感应电压差异,因此选择中期信号区间的感应电压来分析。在中期信号区间内,凹槽长度或深度增加,金属量减少量增大,则感应电压越小。随着管道埋深增大,感应电压逐渐减小。试验得到的规律与仿真模拟一致。不同管径的模拟结果显示,在中期信号区间会出现一个趋势反转点,在反转点以前,随着管径增大,感应电压逐渐减小;在反转点之后,随着管径增大,感应电压逐渐增大。在试验中,中期信号区间放大结果显示,随管径增大,感应电压增大。

Based on the finite difference time domain(FDTD)algorithm,the large-scale pulse eddy current testing of corrosion defects in heating pipeline is simulated and verified by experiment.The annular grooves with different lengths and depths,as well as different pipe diameters and buried depths are simulated by using non-uniform grid-FDTD algorithm.In most cases,the induced voltage difference in the medium term is greater than that in the late term,so the induced voltage in the medium-term signal interval is selected for analysis.In the medium-term signal interval,as the groove length or depth increases,the metal amount reduction increases,so the induction voltage is smaller.As the buried depth of the pipeline increases,the induced voltage decreases gradually.The law obtained from the experiment is consistent with the simulation.The simulation results of different pipe diameters show that there will be a trend reversal point in the medium-term signal interval.Before the reversal point,the induced voltage decreases gradually with the increase of pipe diameter.After the reversal point,the induced voltage increases gradually with the increase of pipe diameter.In the experiment,the amplification results of medium-term signal interval show that the induced voltage increases with the increase of pipe diameter.